Related Experiment Video
Updated: Jul 15, 2026

Application of Chronic Stimulation to Study Contractile Activity-induced Rat Skeletal Muscle Phenotypic Adaptations
Published on: January 25, 2018
Episodic stimulation of alpha1-adrenoreceptors induces protein kinase C-dependent persistent changes in motoneuronal
Natalia V Neverova1, Shane A Saywell, Lisa J Nashold
1Systems Neurobiology Laboratory, Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California 90095-1763, USA.
Abstract:
In vitro long-term facilitation (ivLTF) is a novel form of activity-independent postsynaptic enhancement of AMPA receptor function in hypoglossal (XII) motoneurons that can be induced by intermittent activation of 5-HT2 receptors. In vivo respiratory long-term facilitation (LTF) is characterized by a persistent 5-HT2 receptor-dependent increase in respiratory motor output or ventilation after episodic exposures to hypoxia in adult rats. Here, we demonstrate that ivLTF can also be induced by episodic but not continuous stimulation of alpha1-adrenergic receptors that requires protein kinase C (PKC), but not PKA (protein kinase A), activation. Additionally, we show that in vivo respiratory LTF is also alpha1-adrenergic receptor dependent. We suggest that, in vivo, concurrent episodic activation of 5-HT2 and alpha1-adrenergic receptors is necessary to produce long-lasting changes in the excitability of respiratory motoneurons, possibly involving PKC activation via the G alpha(q)-PLC (phospholipase C) signaling pathway common to both receptor subtypes. Such plasticity of XII motor output may increase upper airway muscle (innervated by XII nerve) tone and improve the likelihood that airway patency will be maintained. Elucidating the mechanism underlying LTF can be of clinical importance to the patients suffering from sleep-disordered breathing.
More Related Videos
Related Concept Videos
cAMP-dependent Protein Kinase Pathways
Motor Unit Stimulation
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
Long-term Potentiation
Hebbian LTP
LTP can occur when presynaptic neurons...
Long-term Potentiation
GPCRs Regulate Adenylyl Cylase Activity
Two...
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.

